Electronic devices such as power tools often include an electrical plug module for coupling with an electrical extension cord, thereby permitting an operator to use the power tool at locations remote from the nearest available electrical outlet. One common configuration for such a system is to include the electrical plug module within a recess of the housing such that prongs of the electrical plug module are accessible to engage the female receptacle disposed on the electrical extension cord. Thus, the electrical extension cord may be coupled to the recessed electrical plug module, with the coupling being at least partially hidden from view and at least partially protected within the power tool housing from becoming dislodged.
However, nearly all power tools produce some jarring and/or vibration of the power tool during operation, which in turn jars and vibrates the coupling between the electrical plug module and the electrical extension cord. The jarring/vibration causes the electrical plug module to vibrate at a different frequency than the extension cord. Due to the different relative vibration, the electrical plug module and electrical extension cord may become at least partially if not totally disengaged from one another, resulting in a loss of power to the power tool and possibly damaging the connection due to electrical arcing, interrupting its operation and usually aggravating the operator.
A retaining clip may be added, which is attached to the same handle/body in which the electric plug module is mounted. When provided, the retaining clip is also configured and arranged to make contact with the extension cord. The retaining clip will thereby transfer to the extension cord the vibration frequency of the handle/body that contains the plug module. The connection will reduce the effect of relative vibration and help prevent the cord from backing out. However, due to the wide range of extension cord female plug shapes, the retainer clip may make the female plug insertion difficult and may aggravate the operator. In addition, some plug shapes may not be as effective as others. The elimination of the retainer clip is desirable from an operator prospective.
In addition, where the power tools are portable, and are releasably coupled to an extension cord, inadvertent pulling or catching of the extension cord may cause the extension cord to become disengaged. For example, operators will frequently though inadvisably handle the power tool by the extension cord, and often times the weight of the power tool itself is greater than the amount of force required to disengage the extension cord from the tool. Other times the extension cord will become caught or snagged on a portion of the work surface or other part of the environment, and as the operator moves the power tool during operation, the operator inadvertently pulls the power tool away and disengages from the extension cord.